With our firstborn, we started with a couple varieties of microwave steam sterilizer. These come in two basic flavors; disposable and durable. The durable kind is basically an enclosed drying rack with a tray underneath for water. Put water in the tray, fill up the rack, place in the microwave for 6-10 minutes, and viola, sterilized bottles.
The disposable kind is simply a plastic zip-lock bag with a steam vent and much the same purpose and method of operation. It's only good for 10 or so uses after which the manufacturer recommends you throw it away, but the advantage is the bag can be rolled up, stuffed in a diaper bag and used wherever you have access to a microwave.
We quickly learned that taking this extra step is a huge hassle, and given that we were using an antibacterial dish soap to hand-wash the bottles, it was also completely unnecessary.
We eventually just went with putting them in the dishwasher, which is our current method. Our 16-month-old still refuses to try a sippy cup, so we use a bottle at every meal and for "milk snacks" and general hydration in between, and that adds up to a lot of bottles to wash. The dishwasher actually does a better job of sanitizing what you wash in it than the steam sterilizers, and if you're willing to tolerate a melted part or two (happens even with the best cages to contain the nipples and other parts; Babies R Us stocks plenty of spare parts for a good reason), it's a lot easier.
Tips for anyone who's gonna use heat to sterilize:
If you go plastic, use polypropylene bottles with silicone nipples. Polypropylene is at this point the best overall choice for a baby bottle; the plastic is made without any phthalates or bisphenols to cause problems (Bisphenol-A or BPA is not the only bisphenol compound used in polycarbonate plastics, and they're pretty much all bad news but only BPA is illegal, so manufacturers simply switch to another bisphenol, and voila, BPA-free), and it's a relatively durable, thermally-resistant (microwave-safe) and chemically-resistant plastic (though it does have a tendency to absorb dyes in the presence of an acid, for instance tomato juice stains). Silicone rubber is similarly pthalate and bisphenol-free, thermally stable (it's used for oven mitts and trivets), and more durable and chemical-resistant than rubber compounds. My wife and I use the Playtex VentAire Advanced bottles, which are made from these materials (though be careful with hand-me-downs, because they weren't always).
Polycarbonate plastics are bad. They just are. Not only are they not as thermally-resistant (you'll end up seeing stress fractures in key places in the plastic after several runs through a sterilizer or dishwasher), but because of that, they'll break down and leach their monomer into whatever they hold. This monomer is invariably a bisphenol compound; polycarbonate plastics are composed of bisphenol monomers by definition. As I mentioned above, BPA isn't the only bisphenol compound, it's just the most infamous as it was widely used in products like Plexiglas and Lexan (still is, in non-food applications), so while a manufacturer can legally claim its product is BPA-free, the bisphenol variant he does use isn't any better for your baby.
Glass would be ideal chemically, as it's almost totally inert and highly thermally resistant. It just has that one pesky side effect of shattering into sharp pieces on impact, which is especially problematic for my wife and I because our daughter has developed the habit of throwing the empties onto the floor, because she likes the clatter they make. If your child isn't yet able to hold the bottle themselves, glass is best all around.
When doing a dishwasher load including bottles, make sure everything in that load is well-rinsed - You'll reduce occurrences of a baby bottle part getting the roast beef from last night's dinner stuck in some crevice. In addition, some things in milk and formula are harder for a dishwasher to remove, especially if they've been allowed to set for some hours.
Don't use a rinse aid with plastic bottles in the dishwasher - The bulk of most dishwasher detergents is a weak base, like sodium carbonate. This raises the pH of the water to help dissolve proteins and acidic food residues. It's not really a "water softener" though it can be called that; in fact most of them actually increase alkalinity ("hardness"), which causes the water spots. The active ingredient of a rinse aid is a "chelating agent" (aka an acid), which dissolves this alkalinity, leaving behind spotless dishes. However, plastics will, over time, react to the acid in the rinse water. Even polypropylene (as previously mentioned, it will discolor and eventually degrade in an acidic environment). That would mean using tablets or gel packs that have rinse aid built into them, and a separate supply of dish detergent without a rinse aid, so you can choose when you need it and when you don't on a per-load basis. It will probably also mean no glassware in the same load as plastic bottles. Hey, you sort your laundry by color and fabric, right? (well, we don't anymore; with one baby requiring our attention and another on the way, it's a miracle we have clean clothes in the first place).
Hand-wash every so often to remove hard water clouding - Silicone and other soft parts are especially vulnerable to clouding with hard water buildup. It's not harmful (and you should get your baby used to your local tap water as soon as they're off of a breastmilk-only diet), and it comes off with a good scrub (no abrasives please). Since you're not using a rinse aid for the wash cycle, it can't hurt to give the rest of the bottle a good hand-wash every few cycles as well.
Don't go overboard - Your baby's immune system is tougher than you think, and it needs to be, given what your baby will be getting into over the next three or four years when you're not looking. It's currently thought that our obsession as parents with eradicating every germ in sight is actually increasing the incidence of conditions like asthma and allergies, because the immune system, in the absence of real threats, overreacts to very minor pathogens or even non-pathogens. It's now becoming encouraged for parents to, for instance, clean their baby's pacifiers by sticking them in their own mouths. By doing so, you give your baby a dose of the same bacterial colonies that call your body home, many of which, far from being parasitic, are actually essential for human life.